Standard&Poor's Ratings Services has raised its rating on Austin, Texas's airport system revenue bonds to 'A' from 'A-'. The outlook is stable. The upgrade reflects our view of sustained financial performance and solid enplanement trends in the past three years relative to those of other airports across the U.S. The rating reflects our assessment of the following factors: Austin Bergstrom International Airport (ABIA) has a strong origin and destination market (more than 95%) and good diversity of carriers with Southwest Airlines Co., American Airlines Inc., and Continental Airlines Inc. accounting for 79% of enplanements in 2010. ABIA has experienced solid enplanements growth, with passenger traffic rising an average of 4.5% a year during the past 10 to reach